Early computer designs generally included a chassis with a plurality of individual components and assemblies mounted therein and connected to one another by means of wires, cables, brackets, nuts, bolts and the like. A major computer design advance occurred with the advent of printed circuit boards, integrated circuits and modular component assemblies. The printed circuit boards were, for example, formed of lightweight material and housed a myriad of components which were electrically interconnected with the component assemblies through wiring harnesses. The wiring harnesses and hard wire connections were subsequently replaced by technologically advanced connectors used for integrally coupling the individual components to each other and to other circuitry in the computer.
In the design of electronic equipment, the use of connectors, modular components, and specialized hardware has permitted key components and printed circuit boards to be efficiently added and removed. Such ease in the addition and deletion of computer components and printed circuit boards has facilitated assembly repair, upgrade, and/or changes in functionality.
Computer reliability and serviceability are also valuable design aspects. Originally, a rule of practice in the maintenance of electrical circuitry, such as computer hardware, was that of always turning the power to the computer off before components or printed circuit boards were added or removed from the computer chassis or support frame. Recent innovations have addressed the desirability to insert and remove modular components and printed cards from electrical equipment, such as computer hardware, when the computer is electrically connected and operational, i.e. "hot." This is now possible for hot pluggable hard drives, and in these cases, the power may be disconnected from only the connector of the drive or modular component to be inserted and removed while allowing the adjacent components to remain "hot."
Removable computer components today include disc drives, drive cages, fans, power supplies, system I/O modules, processor boards, and other subassemblies. As referenced above, the removability of computer components allows for better overall serviceability of the computer system, which is a distinct advantage to both the user and the maintenance technician. A defective power supply in the main or central computer generally requires prompt replacement in order to limit downtime. It is for this reason that modular components and connectors facilitate prompt replacement and are thus popular in many computer designs.
The modularity of computer systems is thus recognized as an important design consideration. As referenced above, modules can be removed and examined for operability or other purposes much easier than permanently mounted fixtures within a computer chassis. Because computers provide an integral part of most business operations, it is of utmost importance to maintain the reliability and integrity of the computer system. When the various elements of a computer can be easily removed in a modular form, they can also be replaced to maintain the operational status of the computer.
Many current design approaches for these types of modular computer components utilize metal brackets secured with screws to the computer chassis or support housing to secure and maintain the component therein. This design presents many problems, as the brackets are often difficult to access and require extra time for alignment during the installation of the component within the component connector and the housing. Similarly, extra time is needed to remove and store all of the screws prior to the removal of the component from the connector and the housing. Additionally, tools are typically needed to be able to install and remove the brackets from the component and the housing, and the component must be moved relative to the connector in order to install or remove it.
Therefore it is desirable to have a modular computer chassis that can be serviced and upgraded with minimum tools with respect to not only the addition of computer components, but also with the removing and installing of the access panels.